y, z} y B = { , , , , }: R = {(a, ), (c, ), (x, ), (y, ), (z, )} R = {(a, ), (a, ), (c, ), (x, ), (x, )} R = {(a, ), (b, ), (c, ), (x, )} R = {(a, ), (b, ), (b, ), (c, ), (c, ), (x, ), (y, )} DOM(R ) = {a, c, x, y, z} RAN(R ) = { , , } DOM(R ) = {a, c, x} RAN(R ) = { , , , , } DOM(R ) = {a, b, c, x} RAN(R ) = { , , , }